The present invention relates generally to wafer handling and processing, and more particularly to a method for ultra thin wafer handling and processing.
In the semiconductor industry, efforts to reduce the thickness of a semiconductor wafer are in progress to respond to the goals of reducing the thickness of semiconductor packages, to increase the chip speed, and for enabling high-density fabrication. However, with thinned dimensions, these ultra thin wafers are too fragile to reliably handle or manipulate during process steps, such as dicing the wafer into individual chip packages. They have insufficient strength and are more susceptible to cracking and deformation, such as bending and/or warping. One way of handling the ultra thin wafer is to encapsulate it in a molding compound, such as thermocuring epoxy resin.
However, encapsulating an ultra thin wafer in a molding compound during handling and processing is not without its drawbacks. Where the molding compound has become undone or delaminated from the wafer to which it is attached to, the wafer may be subject to warpage. Wafer warpage is detrimental to the fabrication process and tends to decrease the overall process yield and may degrade the quality and reliability of the chip packages that are produced. Moreover, where molding delamination from the wafer has occurred, the edges of the wafer may be more susceptible to cracking, chipping, and/or corrosive environmental influences during the subsequent dicing process and associated handling. In stacked chips, heat becomes an issue. Molding compounds generally accumulate an excessive amount of heat, which then impacts device performance.
For these reasons and other reasons that will become apparent upon reading the following detailed description, there is a need for an improved method of handling and processing ultra thin wafers that avoids the shortcomings of conventional methods.